Perhaps you're not aware that Inuit lived without plants for most of the year and did well?
Maybe take a look at this documentary, which touches on the story of a vegetarian who ended up living with the Inuit and his experiences. It's a good place to start to expand your knowledge.
https://www.youtube.com/watch?v=iVJM_0XEiBI&pp=ygUPZmF0IGRvY...